Manchester United need Wayne Rooney - Carlo Ancelotti
Berbatov (left) looks on as Chelsea players celebrate at Old Trafford
Chelsea boss Carlo Ancelotti says title rivals Manchester United are a weaker side without striker Wayne Rooney.
An ankle injury meant Rooney missed United's 2-1 home loss to the Blues on Saturday, which leaves league leaders Chelsea two points clear of United.
"They're not the same team without him," claimed Ancelotti. "Rooney is a fantastic player who is difficult to replace with anyone else."
The 24-year-old is expected to be out for around two more weeks.
Rooney, who has scored 34 goals for United in all competitions this season, suffered minor ligament damage in the closing stages of United's 2-1 Champions League quarter-final first leg defeat at Bayern Munich last Tuesday
It's not easy for United to maintain their characteristic and momentum without Rooney but they have the possibility to move on and I hope they get to the semi-final
In his absence, United manager Sir Alex Ferguson opted to play Dimitar Berbatov in the lone striker role usually occupied by the England man in Saturday's defeat to Chelsea at Old Trafford.
However, Ancelotti feels the two playing style of the two strikers is incomparable.
"[Dimitar] Berbatov is good but Rooney is totally different," explained the 50-year-old Italian.
"Rooney can sometimes come back to receive the ball and use it for all the team and then he can attack in any direction. He is an unbelievable player."
With five games to go in the Premier League, Ancelotti feels the title momentum is now in favour of his side, who as well as holding a two-point advantage over United and three-point lead over third-place Arsenal, have a superior goal difference to their rivals.
"It is not a good moment for United after losing to Bayern during the week and because they have lost a very important player," added Ancelotti, whose side were eliminated from the Champions League at the last-16 phase by Inter Milan.
"It's not easy for United to maintain their characteristic and momentum without Rooney but they have the possibility to move on and I hope they get to the semi-final."
Newspaper reports on Monday morning suggested Rooney's recovery is going quicker than anticipated and that he may play some part in the Champions League second leg against Munich on Wednesday, but there has been no official confirmation of this from the club.
With or without Rooney, viewed as being a crucial component for Fabio Capello's England, United will need to make Premier League history if they are to retain their Premier League crown.
Saturday's loss to Chelsea, courtesy of goals from Joe Cole and Didier Drogba before Federico Macheda's late consolation, was their seventh defeat of the season and no side has lifted the trophy having suffered so many losses in a 38-game campaign.
Meanwhile, Arsenal's title chances looked to be slipping away from them at the Emirates against Wolves before Nicklas Bentner's goal four minutes into injury-time kept them in the title race.
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